1. Field of the Invention
The present invention relates to multi-way selector valves such as three-way selector valves, four-way selector valves, and the like that are used in refrigeration cycles and the like, and more particularly to rotary multi-way selector valves that switch flow paths by rotating a valve member with an actuator, such as a motor comprising a rotor and a stator, or the like.
2. Background Art
In general, refrigeration cycles of air-conditioners, refrigerators and the like comprise a compressor, a gas-liquid separator, a condenser (outdoor heat exchanger), an evaporator (indoor heat exchanger), an expansion valve, and the like, as well as a four-way selector valve as a flow path (flow direction) selector means.
An example of such a refrigeration cycle comprising a four-way selector valve will be described with reference to FIG. 5 and FIG. 6. A refrigeration cycle 300 in the illustrated example is for an air-conditioner and performs the switching of operation modes (cooling operation and heating operation) with a four-way selector valve 320. Specifically, it comprises a compressor 310, a gas-liquid separator 312, a condenser (outdoor heat exchanger) 314, an evaporator (indoor heat exchanger) 316, and an expansion valve 318. Amid the above-mentioned four units, namely, the compressor 310, the gas-liquid separator 312, the condenser 314, and the evaporator 316, there is disposed the four-way selector valve 320, which has four ports (inlets/outlets), namely, first to fourth ports a, b, c, and d (see FIG. 6).
Each of the units mentioned above are interconnected with flow paths formed by conduits (pipes) and the like. Specifically, there are provided: an inlet flow path 321 that routes the refrigerant inside the gas-liquid separator 312 to the compressor 310; a discharge flow path 322 that routes the high-pressure refrigerant discharged from the compressor 310 to the first port a of the four-way selector valve 320; a condenser-side feed/return flow path 323 that connects the second port b of the four-way selector valve 320 and a first throughlet 314a of the condenser 314; an evaporator-side feed/return flow path 324 that connects the third port c of the four-way selector valve 320 and a first throughlet 316a of the evaporator 316; a return flow path 325 that connects the fourth port d of the four-way selector valve 320 and a return port 312a of the gas-liquid separator 312; a flow path 326 that connects a second throughlet 314b of the condenser 314 and the expansion valve 318; and a flow path 327 that connects the expansion valve 318 and a second throughlet 316b of the evaporator 316.
With the refrigeration cycle 300 of such a configuration, when the cooling operation mode is selected, the four-way selector valve 320 is switched to a state that communicates the discharge flow path 322 with the condenser-side feed/return flow path 323, while at the same time communicating the evaporator-side feed/return flow path 324 with the return flow path 325 as shown in FIG. 6(A). In this case, as indicated with the solid arrows in FIG. 5, the low-pressure refrigerant within the gas-liquid separator 312 enters the compressor 310 via the inlet flow path 321, while a high-temperature high-pressure refrigerant is routed from a discharge port 310a of the compressor 310 to the condenser 314 via the discharge flow path 322, the four-way selector valve 320 and the condenser-side feed/return flow path 323, exchanges heat with the outdoor air and is condensed at the condenser 314 to become a high-pressure two-phase refrigerant, and is introduced to the expansion valve 318 via the flow path 326. The pressure of the high-pressure refrigerant is reduced by this expansion valve 318, and the low-pressure refrigerant whose pressure has been reduced is introduced into the evaporator 316 via the flow path 327, exchanges heat with the indoor air (cooling) here and evaporates. From the evaporator 316, a low-temperature low-pressure refrigerant is returned to the gas-liquid separator 312 via the evaporator-side feed/return flow path 324, the four-way selector valve 320, and the return flow path 325.
In contrast, when the heating operation mode is selected, the four-way selector valve 320 is switched to a state that communicates the discharge flow path 322 with the evaporator-side feed/return flow path 324, while at the same time communicating the condenser-side feed/return flow path 323 with the return flow path 325 as shown in FIG. 6(B). In this case, as indicated with the dashed arrows in FIG. 5, the refrigerant within the gas-liquid separator 312 enters the compressor 310 via the inlet flow path 321, while a high-temperature high-pressure refrigerant is routed from the discharge port 310a of the compressor 310 to the evaporator 316 via the discharge flow path 322, the four-way selector valve 320 and the evaporator-side feed/return flow path 324, exchanges heat with the indoor air (heating) and evaporates at the evaporator 316 to become a high-pressure two-phase refrigerant, and is introduced to the expansion valve 318 via the flow path 327. The pressure of the high-pressure refrigerant is reduced by this expansion valve 318, and the low-pressure refrigerant whose pressure has been reduced is introduced into the condenser 314 via the flow path 326, exchanges heat with the outdoor air here and condenses. From the condenser 314, a low-temperature low-pressure refrigerant is returned to the gas-liquid separator 312 via the condenser-side feed/return flow path 323, the four-way selector valve 320, and the return flow path 325.
A rotary four-way selector valve that is incorporated into a refrigeration cycle such as that mentioned above basically comprises, as can be seen in Patent Document 1 indicated below: a valve member that is rotated by an actuator such as a motor or the like; and a valve body that rotatably holds the valve member and has a valve seat portion and a valve chest, wherein a first inlet/outlet (condenser communicating port), a second inlet/outlet (evaporator communicating port), a high-pressure inlet for introducing a high-pressure refrigerant from the compressor discharge side into the valve chest, and a low-pressure outlet for venting the low-pressure refrigerant to the compressor inlet side are provided in the valve seat portion of this valve body, and the switching of flow paths is performed by selectively communicating, by rotating the valve member, one of the first inlet/outlet and the second inlet/outlet with one of the high-pressure inlet (valve chest) and the low-pressure outlet by means of a passage portion provided within the valve member.
However, a conventional rotary four-way selector valve such as that described above had problems in that the pressure difference between the inside and the outside of the valve member becomes extremely large due to the fact that a high-pressure refrigerant is introduced into the valve chest while a low-pressure refrigerant is made to flow through the passage portion within the valve member, and the valve member is pressed strongly against the valve seat portion due to that pressure difference (the high-pressure refrigerant), resulting in a tendency for the valve member to not rotate smoothly at the time of flow path switching, thereby making the flow path switching operation heavy, and in that the valve member and the valve seat portion are prone to wear.
In order to solve such problems, the present inventors had previously proposed a four-way selector valve of such a configuration as follows (Patent Document 2 indicated below).
Specifically, as shown in FIG. 3 and FIG. 4, this previously-proposed four-way selector valve 1′ comprises: a valve member 50 that is rotated by an actuator 15 such as a motor or the like so as to switch flow paths; and a valve body 60 that rotatably holds this valve member 50, wherein a high-pressure passage portion 55 to which a high-pressure refrigerant is introduced is formed in the valve member 50, the valve body 60 is provided with a valve seat portion 65 that has a first inlet/outlet 13 and a second inlet/outlet 14 that are selectively communicated with the outlet side of the high-pressure passage portion 55, and a valve chest 61 into which a low-pressure refrigerant is selectively introduced via the first inlet/outlet 13 and the second inlet/outlet 14, an outlet-side end portion of the high-pressure passage portion 55 of the valve member 50 is made to slide between the first inlet/outlet 13 and the second inlet/outlet 14 in the valve seat portion 65 at the time of flow path switching, and the shapes and dimensions of the valve member 50 and the like (namely, the outer diameter of a lower end portion 54 of an inverted L-shaped shaft portion 53, the effective inner diameter of a square ring 75, and the like) are set in such a manner that the force in the direction in which the valve member 50 is pressed against the valve seat portion 65 by the high-pressure refrigerant is substantially canceled.
More specifically, the valve member 50 has the inverted L-shaped shaft portion 53, and the crank shaped or inverted L-shaped high-pressure passage portion 55 for selectively routing the high-pressure refrigerant to the first inlet/outlet 13 and the second inlet/outlet 14 is formed within the inverted L-shaped shaft portion 53. In addition, a high-pressure inlet 11 for routing the high-pressure fluid to the high-pressure passage portion 55 of the valve member 50 is provided in a bottom portion of the valve chest 61 on the side opposite the valve seat portion 65. Further, a low-pressure outlet 12 that opens to the valve chest 61 is provided. It is thus made to function as a four-way selector valve used in the above-mentioned refrigeration cycle.
In this proposed four-Way selector valve 1′, the high-pressure passage portion 55 to which the high-pressure refrigerant is introduced is formed within the valve member 50, while at the same time an arrangement is made such that the low-pressure refrigerant is introduced into the valve chest 61, and the shapes and dimensions of the valve member 50 and the like are so set as to substantially cancel the force in the direction in which the valve member 50 is pressed against the valve seat portion 65 by the high-pressure refrigerant. Thus, flow path switching operations can be performed with ease, while at the same time the valve member 50 and the valve seat portion 65 become less prone to wear and, consequently, durability and reliability are improved.
[Patent Document 1] JP Patent Publication (Kokai) No. 2001-295951 A
[Patent Document 2] JP Patent Application No. 2009-098188